Draft control device



June 13, 1939. I a. w. FRANKS 2,161,809

DRAFT CONTROL DEVICE Original Filed June 28, 1954 Elma/whom T j 1 l rd/7A5 Gum/M114 Patented June 13, 1939 .1

DRfA-FT ooNTnoL DEVICE j ,it ye jw; sta rs, Salt Lake City, can .f 1 Original application June 28,'1934,"Serial No. 732,810. Divided and this amilic'ation September 10,1935, Serial No. 39,941 V cfo aiins: (01. 236-45) My invention relates todraft control .devices, and-has for its object to. provide anew and efficient draft control devicewhich willcontrol the draft in the flue andgprevent any draftthrough the furnace when it is not: burning and which at the same time will prevent any excessive draft through the fire box when the fire is burning.

A further object is to provide a control system for controlling the draft through furnaces and in- 10 dustrial furnaces through the control of the fuel supply in coordination and cooperation with the control device to shut off draft through the furnace when the fuel is shut off..

A still further object is to provide a control device for furnaces in which the device is controlled by the fuel supply or the steam generated in the boiler and also to provide a device acting independently to limit draft through the fire box of the furnace and prevent excessive draft therethrough.

A still further object is to provide a draft control device which will save fuel in the quantity used and which will produce greater heat and efficiency from the fuel used in the furnace.

These objects I accomplish with the device illustrated in the accompanying drawing in which similar numerals and letters of reference indicate like parts throughout the several views and as described in the specfication forming a part of this application and pointed out in the appended claims.

In the drawing Figure 1 is a vertical section of the device.

Figure 2 is a. side elevation of Figure 1.

Figure 3 is a plan view of the control valve used in Figure 1.

Figure 4 is a vertical longitudinal section of a modified form of valve used in the casing.

This application is a division of the application filed by me on June 28, 1934, for Draft control device, Serial No. 732,810.

In the drawing in which I have shown the preferred manner of building my device, the casing is shown as G, with a flange formed on 5 one end to secure the casing into open connecton with the flue K and with the end 6| open. A control plate valve 62 is mounted medially of the casing G with stub shafts 63 and 64 mounted on each side thereof to support the plate and 50 these shafts extend into suitable bearings carried in the side walls of the casing G. A counterbalance weight 65 is mounted onto a shaft 66 which is secured in a block 61 and the block 61 is secured onto the stub shaft 64.

55 The plate valve 62 is formed with two openings 68 and 69 therethrough and draft responsive plates ld and H aremounted p-ivotally tosaid plate by the pivot bearings 12 so that the plates will normally close the openings 68 and 69. a

The control for the plates consists of a bell 6 crank" arm 13 mounted onto the'top side of the plate valve and a flexible connection 16 connects the arm with a rod M which in turn is connected with the operating shaft of a flexible diaphragm l5 by a connection ll. The power cham- 10 ber of the diaphragm is then connected with either air pressure, steam pressure or any other pressure which may be utilized to control the opening and closing of the plate valve 62.

In Figure 4 the longitudinal plate valve 88 is 15 mounted from one end on a rod 89 which is carried in suitable bearings in the casing 90 and a counterbalance rod extends beyond the rod89 to counterbalance the weight of the plate valve 88 by the adjustable weight 92 carried thereon. 20

The two openings 93 and 94 are formed through the valve and are controlled by draft responsive plates 95 and 96. A flexible diaphragm 91 is used to control the valve 88.

Having thus described my invention I desire to 5 secure by Letters Patent and claim:

1 In a draft control device, the combination of a casing adapted to be mounted on the flue of a furnace in open connection therewith, but notin the path of travel of the consumed gases; a 30 perforated plate having openings therein and pivotally mounted medially thereof and resting diagonally across said casing when in closed position; draft plates mounted on said plate to control said openings; means to open said plate by 35 pressure; and means to counterbalance said plate.

2. In a draft responsive draft control device of the class described, the combination of a casing adapted to be mounted on the flue of a furnace, but not in the path of travel of the consumed 40 gases; a draft control plate having openings therein and pivotally mounted in said casing and resting diagonally across said casing when in closed position; means to counterbalance said plate; draft responsive plates mounted on said 45 plate to control said openings; and means to control said plate.

3. In a draft control device, the combination of a rectangular casing having one end mounted into open connection with the flue pipe of a fur- 50 nace; a control plate mounted with the center of pivot medially thereof and to set diagonally of said casing when in the closed position; a shaft extending through one side of said casing from the pivotal mounting of said plate; an arm ex- 55 tended from said shaft; a weight adjustably mounted on said arm to counterbalance said plate; large openings through said plate one above and one below the pivotal mounting of said plate; draft responsive plates mounted to close said openings in said plate, but to open when excessive draft is passing up through the flue pipe of the furnace to relieve the draft in said furnace; a diaphragm mounted in connection with said plate, said diaphragm to open or close said plate independently of said draft responsive plates. 7

4. In a draft control device, the combination of a rectangular casing mounted onto one side'of a furnace flue pipe in open connection therewith,

but not in the path of travel of the consumed gases 'from' the furnace; a draft control plate mounted with one end pivoted to the casing near 7 one end and at the top edge thereof with the 5. In a draft control device, the combination of a rectangular casing mounted. onto one side of a furnace flue in open connection therewith but, not in the path of travel of the consumed gases from the furnace; a draft control plate pivotally mounted diagonally lengthwise of said casing, said plate having openings therein; draft responsive plates mounted over said openings said plates to be raised when excessive draft conditions occur in the furnace pipe to relieve the draft through the furnace; an arm mounted to operate said plate; a link connected to said arm; and a dia: phragm mounted on said casing with said link connected to one side thereof, said diaphragm to open or close said valve. 7 i

6. A check damper mechanism for furnaces having a flue and comprising a main flue damper. means operable in response to predetermined heat conditions to open and close the main damper, a supplemental damper carried by the main damper and movable to open and closed positions, independently of the main damper, means mounting said supplemental damper for movement to said positions consequent upon a differential in pressure within and outside the flue.

ROYE W. FRANKS. 

